Approximately 40% of patients suffering from the sepsis syndrome are infected with Gram negative bacteria. It is this subset of patients that stand to benefit from new therapies designed to neutralize endotoxin such as anti-lipid A monoclonal antibodies (e.g. E5 or HA-1A) and bacterial permeability inducing protein (BPI). Because of the enormous cost of these therapies we plan to develop a simple, sensitive test for early detection of Gram negative bacteremia. Our hypothesis is that conserved regions exist in certain genes of Gram negative bacteria that can serve as targets for rapid and sensitive diagnosis of these lethal pathogens. Preliminary data suggest that there are in fact highly conserved regions that can be used to design PCR primers for detection of small numbers of bacteria. Phase I goals will refine the use of this test by determining the sensitivity and specificity using a large set of clinical bacterial isolates from various body fluids. Evaluation of the test in a field trial in suspected septic patients will be carried out in Phase II. Introduction of this test into clinical practice should save millions of dollars spent on the unnecessary use of new and very expensive therapies for gram negative sepsis.